7 A small metal ball is suspended from a fixed point by means of a string, as shown in Fig. 4.1. string ball Fig. 4.1 The ball is pulled a small distance to one side and then released. The variation with time t of the horizontal displacement x of the ball is shown in Fig. 4.2. x /cm 4. 0.8 1/s 1 - 2 Fig. 4.2 The motion of the ball is simple harmonic. (a) Use data from Fig. 4.2 to determine the horizontal acceleration of the ball for a displacement x of 2.0cm. acceleration = .(b) The maximum kinetic energy of the ball is Ek. On the axes of Fig. 4.3, sketch a graph to show the variation with time t of the kinetic energy of the ball for the first 1.0s of its motion. kinetic energy EK OH To.2 0 4 TO.6 40.8 1/s-10 Fig. 4.3 [3]